A large number of medical diagnostic and therapeutic procedures involve the percutaneous introduction of instrumentation into the blood vessel. For example, coronary angioplasty, angiography, atherectomy, stenting, and numerous other procedures often involve accessing the vasculature through placement of a catheter or other device in a patient's femoral artery or other blood vessel. Once the procedure is completed and the catheter or other diagnostic or therapeutic device is removed, bleeding from the resultant vascular puncture must be stopped.
Traditionally, a medical practitioner applies external pressure to the puncture site to stem bleeding until hemostasis occurs (i.e. when the clotting and tissue rebuilding have sealed the puncture). This method, however, presents numerous problems. In some instances, this pressure must be applied for up to an hour or more, during which time the patient is uncomfortably immobilized. In addition, there exists a risk of hematoma since bleeding from the puncture may continue until sufficient clotting occurs, particularly if the patient moves during the clotting process. Furthermore, application of external pressure to stop bleeding may be unsuitable for patients with substantial amounts of subcutaneous adipose tissue since the skin surface may be a considerable distance from the puncture site, thereby rendering external compression less effective.
Another traditional approach to subcutaneous puncture closure comprises having a medical practitioner internally suture the vessel puncture. This method, however, often requires a complex procedure and requires considerable skill by the medical practitioner.
Apparatus and methods also are known in which a plug is introduced into the vessel puncture, to cover the puncture and promote hemostasis. Various types of plugs have been proposed. One example is described in U.S. Pat. No. 5,061,274 to Kensey, comprising a plug made from animal-derived collagen. Such apparatus may be unsuitable for some patients due to an adverse immunological reaction to animal-derived collagen. Furthermore, a plug inserted into the puncture may be dislodged into the vessel during the healing process due to the application of pressure to the wound, potentially causing stenosis of the vessel.
Mechanical occlusion devices have been proposed for sealing, e.g., atrial septal defects, and typically comprise two expandable disks that sealingly compress tissue surrounding the hole. One such device is described in U.S. Pat. No. 5,425,744 to Fagan et al. That device has several drawbacks: (1) it does not permit the device to be repositioned once it is deployed at the puncture without inflicting additional trauma on the engaged tissue; and (2) when deployed into a vessel, the device may protrude into the blood stream, thereby disturbing blood flow and causing thrombosis of the vessel.
In view of these drawbacks, it would be desirable to provide apparatus for sealing a puncture within a vessel or tissue that provides a low profile when engaged against the vessel or tissue wall.
It also would be desirable to provide apparatus for sealing a puncture within a vessel or tissue that is biodegradable.
It further would be desirable to provide apparatus for sealing a puncture within a vessel or tissue that decreases the likelihood of dislodgement of the apparatus.
It still further would be desirable to provide apparatus for sealing a puncture within a vessel or tissue that would permit a medical practitioner to reposition the apparatus after it has been deployed, without inflicting additional trauma to the vessel or tissue.